CN102768327B - Method for detecting fault based on GPS synchronous phase differential method and spare power automatic switching device - Google Patents

Abstract

Embodiments of the present invention provide a method for detecting internal and external faults in the bus area based on GPS synchronous phase differential method and a device for self-switching. The synchronous phase differential method obtains the phase angle β of the positive sequence current fault component after the fault relative to the load current before the fault; compares the phase angle β with the preset fixed value δ; the fixed value δ is based on line parameters and power flow direction set; if the phase angle β is greater than δ, it is judged that there is a fault outside the bus area; otherwise, it is judged that there is a fault in the bus area. The method for detecting internal and external faults in the bus area based on the GPS synchronous phase differential method and the automatic switch-on device provided by the present invention can also judge the type of fault when there is a fault in a substation without bus protection equipment, and avoid blind automatic switch-on when a fault occurs in the bus area , expanding the fault area.

Description

Fault detection method based on GPS synchronous phase difference method and automatic switch-on device

technical field

The present invention relates to a power system protection device, in particular to a method for detecting faults inside and outside the busbar area based on the GPS (Global Positioning System) synchronous phase differential method, and a corresponding method for detecting busbars based on the GPS synchronous phase differential method The device for automatically putting into use the backup power supply for internal and external failures (hereinafter referred to as "preparation and automatic switching device").

Background technique

Identifying bus area faults (bus faults and outgoing side faults) is the main task of bus protection equipment. For substations of 220kV and above, bus protection equipment is installed, and the automatic switching device can use the action blocking signal sent by the bus protection device. To distinguish the fault type when the system fails, whether it is a bus area fault or a line area fault, so as to ensure that when the line area fails, the backup automatic switching device will operate correctly, and the bus fault will block the backup automatic switching device.

Refer to Figure 1, Figure 1 is a typical primary main wiring diagram of a 110kV substation. In this primary system, a typical single-bus section wiring method. During normal operation, there is an open loop point, which constitutes the open mode of standby automatic switching. For example, line 1 is running, the section switch is closed, and line 2 is in standby, which forms a backup self-injection mode with one master and one backup. In the case of the above-mentioned one main and one backup operation mode, when the operation line fails, resulting in the loss of voltage in the whole station, and the device meets the operating conditions, the backup self-injection device will first isolate the fault point and delay the operation of the main supply line switch. After ensuring that the fault point is isolated, switch on line 2 automatically to restore the normal power supply of the bus voltage (as shown in Figure 2).

However, in the substations for 110kV and below, most of them do not have busbar protection equipment, so for a long time, when the power system fails and loses voltage, the standby automatic switching device of 110kV and below cannot distinguish the fault area. The bus area or the line area can only be regarded as the fault of the line area by default, which leads to the blind automatic switching of the backup power supply, so that when the bus area fails, the backup automatic switching device controls the backup power supply and puts it into operation, resulting in the expansion of the fault area.

For the standby automatic switching device of 110kV and below, in order to avoid blind automatic switching in case of a fault in the bus area, resulting in the expansion of the fault area, a new type of standby automatic switching device is required, which can be used in substations without busbar protection equipment. Distinguish between bus area faults and line area faults, so that the power system can accurately and timely automatically turn on the backup power when the line fails, and restore the normal power supply to the load carried by the bus. On the contrary, it can timely and accurately lock the device when the bus fails.

Contents of the invention

The technical problem to be solved by the embodiments of the present invention is that for the standby automatic switchover device of 110kV and below, in order to avoid blind automatic switchover in the power system area, resulting in expansion of the fault area, a new type of standby automatic switchover device is needed , in the case that the substation has no busbar protection equipment, it is possible to distinguish the fault in the busbar area or the fault in the line area, so that the power system can accurately and timely automatically turn on the backup power when the line fails, so as to restore the normal power supply to the load carried by the busbar. On the contrary, it can timely and accurately lock the device when the bus fails.

In order to solve the above technical problems, an embodiment of the present invention provides a method for detecting faults inside and outside the busbar area based on the GPS synchronous phase difference method, including:

It is determined that a fault occurs in the power system, and the power system includes: a bus bar area and a line area;

According to the GPS synchronous phase difference method, the phase angle β of the positive sequence current fault component after the fault relative to the load current before the fault is obtained;

Comparing the magnitude between the phase angle β and the preset fixed value δ; the fixed value δ is set according to the line parameters and the flow direction;

If the phase angle β is greater than δ, it is determined that there is a fault outside the bus area; otherwise, it is determined that there is a fault within the bus area.

Wherein, the determination that a fault occurs in the power system includes:

Detecting whether the variation range of the composite voltage of the bus is greater than the threshold value of the variation range of the composite voltage; or whether the three-phase voltage of the bus is lower than the low-voltage threshold of the three-phase voltage;

If the range of change of the composite voltage of the bus is greater than the threshold of the range of change of the composite voltage, or the three-phase voltage of the bus is lower than the low-voltage threshold of the three-phase voltage; then further detect whether the line current suddenly increases and is overcurrent;

If the line current suddenly increases and is overcurrent, it is determined that the power system is faulty; otherwise, it is determined that the power system is normal.

Wherein, the acquisition of the phase angle β of the positive sequence current fault component after the fault relative to the load current before the fault according to the GPS synchronous phase differential method includes:

When the power system is in normal operation, the phase angle of the load current is periodically detected through GPS precise timing equipment;

After determining that a fault occurs in the power system, detecting the phase angle of the positive sequence current fault component after the fault;

According to the GPS synchronous phase difference method, the phase angle β of the positive sequence current fault component after the fault relative to the load current before the fault is obtained.

Wherein, if the phase angle β is greater than δ, it is determined that there is a fault outside the bus area; otherwise, after determining the fault in the bus area, it also includes:

If it is judged that there is a fault in the busbar area, the blocking standby automatic switching device will act;

If it is determined that there is a fault outside the area of the busbar, the backup self-switching device will be triggered to make the backup power supply start to work, and the normal power supply of the load carried by the busbar will be restored.

Wherein, the faults in the bus area include: bus faults and outgoing line faults.

Correspondingly, the embodiment of the present invention also provides a backup automatic switching device for detecting faults inside and outside the bus area based on the GPS synchronous phase difference method, including:

A system fault judging module, used to judge whether there is a fault in the power system, and the power system includes: a bus area and a line area;

The phase angle processing module is used to obtain the phase angle β of the positive sequence current fault component after the fault relative to the load current before the fault according to the GPS synchronous phase differential method; and compare the phase angle β with the preset fixed value δ size; the fixed value δ is set according to line parameters and power flow direction;

The fault position judging module is used to judge the fault outside the bus area when the phase angle β is greater than δ; otherwise, judge the fault in the bus area; the fault in the bus area includes: a bus fault and an outlet side fault.

Wherein, the system failure judgment module includes:

The first detection unit is used to detect whether the variation range of the composite voltage of the bus is greater than the threshold value of the variation range of the composite voltage; or whether the three-phase voltage of the bus is lower than the low-voltage threshold of the three-phase voltage;

The second detection unit is configured to, when the first detection unit detects that the variation range of the bus composite voltage is greater than the composite voltage variation threshold, or the bus three-phase voltage is lower than the three-phase voltage low-voltage threshold, further Detect whether the line current has a sudden increase and overcurrent;

The judging unit is configured to judge that the power system is faulty when the line current increases suddenly and overcurrent; otherwise, judges that the power system is normal.

Wherein, the phase angle processing module includes:

GPS unit, used to provide timing for relevant unit modules through GPS;

The phase angle detection module is used to periodically detect the phase angle of the load current when the power system is in normal operation according to the timing of the GPS unit; and after the power system fails, detect the positive sequence current fault after the fault the phase angle of the component;

The phase angle β acquisition module is used to acquire the phase angle β of the fault component of the positive sequence current after the fault relative to the load current before the fault according to the GPS synchronous phase difference method.

Wherein, the device also includes:

The standby automatic switching control module is used to block the action of the standby automatic switching device when judging a fault in the bus area; when judging a fault outside the bus area, trigger the action of the standby automatic switching device to make the backup power supply work and restore the load on the bus normal power supply.

Implement the method for detecting internal and external faults in the busbar area based on the GPS synchronous phase difference method provided by the embodiment of the present invention and the corresponding standby automatic switch-on device. For substations without busbar protection equipment, it is possible to distinguish between busbar area faults and line area faults, so as to avoid faults in the busbar area. When there is a fault in the busbar area, blind self-switching will cause the fault area to expand. In the case of no busbar protection equipment in the substation, the power system can accurately and timely automatically turn on the backup power when the line area fails, and restore the normal power supply of the load carried by the busbar. On the contrary, it can timely and accurately lock the device when the bus area fails.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Figure 1 is a typical primary main wiring diagram of an existing 110kV substation;

Figure 2 is a flow chart of restoring bus voltage to normal power supply after the existing 110kV substation operating line fails;

Fig. 3 is the schematic flow chart of the first embodiment of the method for detecting internal and external faults in the bus area based on the GPS synchronous phase differential method provided by the present invention;

Fig. 4 is the schematic flow chart of the second embodiment of the method for detecting faults inside and outside the bus area based on the GPS synchronous phase differential method provided by the present invention;

Fig. 5 is the logical schematic diagram of the method for detecting faults inside and outside the busbar area based on the GPS synchronous phase differential method provided by the present invention;

Fig. 6 is a logical schematic diagram of judging internal and external faults in the bus area by the standby automatic switching device provided by this embodiment;

Fig. 7 is a structural schematic diagram of the first embodiment of the backup automatic switching device for detecting faults inside and outside the bus area based on the GPS synchronous phase difference method provided by the present invention;

Fig. 8 is a structural schematic diagram of the second embodiment of the backup automatic switching device for detecting faults inside and outside the bus area based on the GPS synchronous phase difference method provided by the present invention.

Detailed ways

Implementing the method for detecting internal and external faults in the bus area and the corresponding standby automatic switch-on device provided by the embodiment of the present invention can distinguish between a fault in the bus area and a fault in the line area for substations without bus protection equipment, so as to avoid blind failures in the bus area. Self-switching causes the fault area to expand. In the case of no busbar protection equipment in the substation, the power system can accurately and timely automatically turn on the backup power when the line area fails, and restore the normal power supply of the load carried by the busbar. On the contrary, it can timely and accurately lock the device when the bus area fails.

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Referring to Fig. 3, it is a schematic flow chart of the first embodiment of the method for detecting faults inside and outside the bus area based on the GPS synchronous phase difference method provided by the present invention. As shown in the figure, the method includes:

In step S100, it is determined that a fault occurs in the power system, and the power system includes: a bus area and a line area.

Step S101, according to the GPS synchronous phase difference method, the phase angle β of the positive sequence current fault component after the fault relative to the load current before the fault is obtained.

Step S102, comparing the magnitude between the phase angle β and a preset fixed value δ; the fixed value δ is set according to line parameters and power flow direction; if the phase angle β is greater than δ, execute step S103; otherwise, Then step S104 is executed.

Step S103, determining the fault outside the bus area.

Step S104, determining a fault in the bus area.

The method for detecting faults inside and outside the busbar area based on the GPS synchronous phase differential method provided by the embodiment of the present invention can also detect the faulty area for substations without busbar protection equipment, thereby avoiding blind self-switching when a fault occurs in the busbar area, causing The fault area is expanded. In the case of no busbar protection equipment in the substation, the power system can accurately and timely automatically turn on the backup power when the line area fails, and restore the normal power supply of the load carried by the busbar. On the contrary, it can timely and accurately lock the device when the bus area fails.

Referring to FIG. 4 , it is a schematic flowchart of the second embodiment of the method for detecting faults inside and outside the busbar area based on the GPS synchronous phase difference method provided by the present invention. In this embodiment, the flow of the method for detecting faults inside and outside the busbar area based on the GPS synchronous phase difference method will be described in more detail. As shown in Figure 4, the method includes:

Step S200, detecting whether the variation range of the composite voltage of the bus is greater than the threshold value of the variation range of the composite voltage; or whether the three-phase voltage of the bus is lower than the low-voltage threshold of the three-phase voltage.

Step S201, if the variation range of the composite voltage of the bus is greater than the threshold value of the composite voltage variation range, or the three-phase voltage of the bus is lower than the low-voltage threshold of the three-phase voltage, execute step S202.

More specifically, if there is a fault in the power system, except for three-phase faults and long-distance faults, the compound voltage of the bus will change significantly, and the change will fluctuate greatly. If there is a three-phase fault in the system, or a long-distance line fault, although the composite voltage of the bus does not change significantly, it will cause the three-phase voltage of the bus to be very low. Therefore, through step S200 and step S201, it is possible to preliminarily detect whether there is a fault in the power system. In the embodiment of the present invention, the fault in the power system includes: a fault in the bus area and a fault in the line area.

Step S202, further detecting whether the line current suddenly increases and is over-current. If the line current suddenly increases and is overcurrent, it is determined that the power system is faulty; otherwise, it is determined that the power system is normal.

More specifically, according to the analysis of the characteristics of the fault, if the sudden increase of the line current exceeds the fault threshold set by the device, the fault can generally be considered as a fault on the bus side or the outgoing line side, but in special cases (such as the station has a small power supply), after the line fails, the line current may be reversed by the small power supply, resulting in a sudden increase in current. Although the type of fault at the time of the fault cannot be clarified, as long as the bus fault occurs, it must be accompanied by a sudden increase in current. For bus faults, there will be a sudden increase in current, which must be accompanied by a sudden increase in current above a certain larger fault current setting. Therefore, through this step, it can be basically determined whether the power system is faulty.

Step S203, after determining that a fault occurs in the power system, detecting the phase angle of the positive sequence current fault component after the fault. The phase angle of the positive-sequence current fault component after the fault is measured by GPS precise timing equipment.

More specifically, according to the analysis of fault characteristics, when a fault occurs on the line, the power flow of the line will point to the fault point. If the fault is on the line, the direction of the power flow on the line will be reversed or zero. If the fault is in the bus area or If the load goes out of the line, the direction of the power flow on the line will always maintain the original direction. If it is a load outlet fault, the protection cuts off the outlet side switch, the bus returns to normal, and the standby automatic switching does not need to operate. If the protection cut-off switch fails, then the protection will leapfrog and cut off the incoming power supply, causing the bus to lose voltage. Because of this situation, the fault cannot be isolated , so it is equivalent to a bus area fault. Therefore, the failure of the busbar and the fault on the outlet side, which causes the voltage loss of the busbar, is equivalent to the fault in the busbar area.

The combined judgment of steps S200 to S202 clarifies the typical characteristics of system faults, which is called the basic criterion of faults, and this step and the following steps are to further distinguish whether the fault type is a line area fault or a fault type when a fault is judged. The fault in the bus area is the key criterion. The combined application of the two can accurately determine the fault type of the system.

Step S204, according to the GPS synchronous phase difference method, the phase angle β of the positive sequence current fault component after the fault relative to the load current before the fault is obtained. The phase angle of the load current before the fault is obtained by periodically detecting the load current through the GPS precise timing equipment when the power system is in normal operation. And the GPS signal for detecting the load current is synchronized with the GPS signal for detecting the phase angle of the positive sequence current fault component after the fault.

More specifically, as a precise timing device, GPS provides synchronous sampling clock, binary input acquisition clock, calculation clock, interpretation clock and data transmission clock, providing accurate reference points for measurement targets. According to the principle of component current phase under fault, the invention can effectively identify faults inside and outside the bus area.

Step S205, comparing the magnitude between the phase angle β and a preset fixed value δ; the fixed value δ is set according to line parameters and power flow direction; if the phase angle β is greater than δ, execute step S206; otherwise, Execute step S207.

More specifically, this step is realized based on the GPS synchronization signal phase difference method. The phase differential method is a method for judging the fault direction by only using the current information for the current protection of the distribution network containing distributed power sources, which requires the installation of directional elements to ensure the correctness of the action. By analyzing the current characteristics when a short-circuit fault occurs in the distribution network connected to distributed power generation, it is concluded that the phase angle β of the positive sequence current fault component after the fault relative to the load current before the fault has significant differences in different fault directions. Set the setting value δ according to the line parameters and power flow direction. When the fault occurs on the power supply side outside the bus area, β is greater than δ, and when the fault occurs in the bus area, β is less than δ. Therefore, it can be combined with sudden changes in overcurrent and compound voltage. and other conditions to determine the direction and type of the fault (see Figure 5, Figure 5 is a logical schematic diagram of the method for detecting internal and external faults in the bus area based on the GPS synchronous phase difference method provided by the present invention).

In step S206, it is judged that there is a fault outside the area of the bus, and the standby automatic switch-on device is triggered to start the backup power supply to restore the normal power supply to the load carried by the bus.

In step S207, it is judged that there is a fault in the area of the bus, and the operation of the backup automatic switch-on device is blocked to prevent the backup power supply from being put into operation, so as to avoid the expansion of the fault area.

Further, refer to FIG. 6 , which is a logical schematic diagram of judging internal and external faults in the bus area by the standby automatic switching device provided in this embodiment. As shown in the figure, when the bus fails, the first thing to meet is condition 3 bus composite voltage or condition 4 bus voltage three-phase low voltage. At this time, due to the voltage difference, the line current suddenly increases to a large fault current. Thus, condition 1 and condition 2 can be satisfied at the same time, and the basic judgment condition of fault can be reached. Then further judge the type of fault. As described above, when there is a fault in the busbar area, since the flow direction flows into the busbar according to the original flow direction, the sudden change in phase difference at this time is not so obvious. Therefore, the device combines the above current and If it is judged by the voltage and other criteria that it is a fault in the busbar area, the standby automatic switch-on device will be blocked immediately.

As can be seen from the above, the method for detecting faults inside and outside the busbar area based on the GPS synchronous phase difference method provided by the embodiment of the present invention has all the criteria consistent with the traditional backup automatic switch-on device, and does not need to increase any input. On the basis of the quantity, the relevant criteria such as voltage and current are analyzed and fully utilized. The judgment principle is rigorous and reliable. It can be put into application independently of the standby automatic switching device, and can also be upgraded on the original standby automatic switching device.

The method for detecting faults inside and outside the busbar area based on the GPS synchronous phase differential method provided by the embodiment of the present invention can also detect the faulty area for substations without busbar protection equipment, thereby avoiding blind self-switching when a fault occurs in the busbar area, causing The fault area is expanded. In the case of no busbar protection equipment in the substation, the power system can accurately and timely automatically turn on the backup power when the line area fails, and restore the normal power supply of the load carried by the busbar. On the contrary, it can timely and accurately lock the device when the bus area fails.

Referring to FIG. 7 , it is a structural schematic diagram of the first embodiment of the standby automatic switching device for detecting faults inside and outside the bus area based on the GPS synchronous phase difference method provided by the present invention. The device provided in this embodiment can implement the procedure in the first embodiment of the method for detecting faults inside and outside the bus area based on the GPS synchronous phase difference method provided by the present invention. As shown in FIG. 7 , the device includes: a system fault judgment module 1 , a phase angle processing module 2 , and a fault location judgment module 3 .

The system fault judging module 1 is used to judge whether there is a fault in the power system, and the power system includes: a bus area and a line area.

The phase angle processing module 2 is used to obtain the phase angle β of the positive sequence current fault component after the fault relative to the load current before the fault according to the GPS synchronous phase differential method; and compare the phase angle β with the preset fixed value δ The value of δ is set according to line parameters and power flow direction.

The fault position judging module 3 is used to judge the fault outside the bus area when the phase angle β is greater than δ; otherwise, judge the fault in the bus area; the fault in the bus area includes: a bus fault and an outlet side fault.

The backup self-switching device provided by the embodiment of the present invention based on the GPS synchronous phase differential method to detect faults inside and outside the bus area can also detect the faulty area for substations without bus protection equipment, so as to avoid blind automatic switching when there is a fault in the bus area. If the substation has no busbar protection equipment, the power system can accurately and timely automatically turn on the backup power when the line area fails, and restore the normal power supply of the load carried by the busbar. On the contrary, it can timely and accurately lock the device when the bus area fails.

Referring to FIG. 8 , it is a schematic structural diagram of the second embodiment of the backup automatic switching device for detecting faults inside and outside the bus area based on the GPS synchronous phase difference method provided by the present invention. The device provided in this embodiment can implement the process in the second embodiment of the method for detecting faults inside and outside the bus area provided by the present invention. As shown in FIG. 8 , the device includes: a system fault judging module 1 , a phase angle processing module 2 , and a fault location judging module 3 .

The system fault judging module 1 is used to judge whether there is a fault in the power system, and the power system includes: a bus area and a line area. More specifically, the system fault judgment module 1 includes:

The first detection unit 11 is used to detect whether the change range of the composite voltage of the bus is greater than the threshold value of the change range of the composite voltage; or whether the three-phase voltage of the bus is lower than the low-voltage threshold of the three-phase voltage. More specifically, if there is a fault in the power system, except for the three-phase fault and the long-distance fault of the line, the compound voltage of the busbar will change significantly, and the change will fluctuate greatly. If there is a three-phase fault in the system, or a long-distance fault in the line, although the composite voltage of the bus does not change significantly, it will cause the three-phase voltage of the bus to be very low. Therefore, the first detection unit 11 can preliminarily detect whether there is a fault in the power system. In the embodiment of the present invention, the fault in the power system includes: a fault in the bus area and a fault in the line area.

The second detection unit 12 is configured to detect, when the first detection unit 12 detects that the range of change of the composite voltage of the bus is greater than the threshold of the range of change of the composite voltage, or that the three-phase voltage of the bus is lower than the low-voltage threshold of the three-phase voltage , to further detect whether the line current has a sudden increase and is over-current. More specifically, according to the analysis of the characteristics of the fault, if the sudden increase of the line current exceeds the fault threshold set by the device, the fault can generally be considered as a fault on the bus side or the outgoing line side, but in special cases (such as the station has a small power supply), after the line fails, the line current may be reversed by the small power supply, resulting in a sudden increase in current. Although the second detection unit 12 cannot determine the type of the fault, as long as the bus fault occurs, it must be accompanied by a sudden increase in current. For bus faults, there will be a sudden increase in current, which must be accompanied by a sudden increase in current above a certain larger fault current setting. Therefore, the second detection unit 12 can basically determine whether there is a fault in the power system.

The judging unit 13 is configured to judge that the power system is faulty when the line current suddenly increases and over-current; otherwise, judge that the power system is normal. It can be seen from this that the system failure judging module 1 can make a basic criterion of the failure according to the typical characteristics of the system failure. However, the phase angle processing module 2 and the fault location judging module 3 in this embodiment can further distinguish whether the fault type is a line area fault or a bus area fault when the system fault judgment module 1 judges that a fault occurs in the power system, which is a key criterion . The combined application of the two can accurately determine the fault type of the system.

The phase angle processing module 2 is used to obtain the phase angle β of the positive sequence current fault component after the fault relative to the load current before the fault according to the GPS synchronous phase differential method; and compare the phase angle β with the preset fixed value δ The value of δ is set according to line parameters and power flow direction. More specifically, the phase angle processing module 2 includes:

The GPS unit 21 is used to provide timing for relevant unit modules of the fault detection device inside and outside the bus area, such as the phase angle detection module 22 and the phase angle β acquisition module 23 through GPS. As an accurate time service device, GPS provides synchronous sampling clock, binary input acquisition clock, calculation clock, interpretation clock and data transmission clock, providing accurate reference points for measurement targets. According to the principle of component current phase under fault, the invention can effectively identify faults inside and outside the bus area.

The phase angle detection module 22 is used to periodically detect the phase angle of the load current when the power system is in normal operation according to the timing of the GPS unit; and detect the positive sequence current after a fault occurs in the power system Phase angle of the fault component. The GPS signal for detecting the load current is synchronized with the GPS signal for detecting the phase angle of the positive sequence current fault component after the fault.

The phase angle β acquisition module 23 is configured to acquire the phase angle β of the fault component of the positive sequence current after the fault relative to the load current before the fault. More specifically, the phase angle β acquisition module 23 implements the above functions based on the GPS synchronization signal phase difference method. The phase differential method is a method for judging the fault direction by only using the current information for the current protection of the distribution network containing distributed power sources, which requires the installation of directional elements to ensure the correctness of the action. By analyzing the current characteristics of the distribution network connected to distributed power generation when a short-circuit fault occurs, it is concluded that the phase angle β of the positive-sequence current fault component after the fault relative to the load current before the fault has significant differences in different fault directions. Set the setting value δ according to the line parameters and power flow direction. When the fault occurs on the power supply side outside the bus area, β is greater than δ, and when the fault occurs in the bus area, β is less than δ. Therefore, it can combine overcurrent mutation and compound voltage mutation and other conditions to determine the direction and type of the fault (see Figure 5, Figure 5 is a logical schematic diagram of a method for detecting faults inside and outside the bus area based on the GPS synchronous phase difference method).

The fault position judging module 3 is used to judge the fault outside the bus area when the phase angle β is greater than δ; otherwise, judge the fault in the bus area; the fault in the bus area includes: a bus fault and an outlet side fault.

Further, the backup automatic switching device provided in this embodiment for detecting faults inside and outside the bus area based on the GPS synchronous phase difference method further includes: a backup automatic switching control module 4 . The standby automatic switching control module 4 is used to block the action of the standby automatic switching device when the fault location judging module 3 determines a fault in the bus area to avoid the expansion of the fault area; when the fault location judging module 3 judges a fault outside the bus area, trigger the standby automatic switching The device operates to make the backup power supply work and restore the normal power supply of the load carried by the busbar.

Further, refer to FIG. 6 , which is a logical schematic diagram of judging internal and external faults in the bus area by the standby automatic switching device provided in this embodiment. As shown in the figure, when the bus fails, the condition 3 bus composite voltage or the condition 4 bus voltage three-phase low voltage is first met. At this time, due to the voltage difference, the line current suddenly increases to a large fault current. Thus, condition 1 and condition 2 can be satisfied at the same time, and the basic judgment condition of fault can be reached. Then further judge the type of fault. As described above, when there is a fault in the busbar area, since the direction of the power flow flows into the busbar according to the original direction of the power flow, the sudden change in phase difference at this time is not so obvious. Therefore, the device combines the above current and If it is judged by the voltage and other criteria that it is a fault in the busbar area, the standby automatic switch-on device will be blocked immediately.

From the above, it can be seen that the backup automatic switching device provided by the embodiment of the present invention based on the GPS synchronous phase difference method to detect faults inside and outside the bus area, all the criteria are consistent with the traditional backup automatic switching device, no need to increase any input, just On the basis of the original input, analyze the relevant criteria such as voltage and current, and make full use of it. The judgment principle is rigorous and reliable. It can be put into application independently of the standby automatic input device, and can also be upgraded on the original standby automatic input device. accomplish.

The backup self-switching device provided by the embodiment of the present invention based on the GPS synchronous phase differential method to detect faults inside and outside the bus area can also detect the faulty area for substations without bus protection equipment, so as to avoid blind automatic switching when there is a fault in the bus area. If the substation has no busbar protection equipment, the power system can accurately and timely automatically turn on the backup power when the line area fails, and restore the normal power supply of the load carried by the busbar. On the contrary, it can timely and accurately lock the device when the bus area fails.

Further, compared with the previous standby automatic switchover device provided by this embodiment, the fault type can be distinguished without adding wiring, which increases the reliability of the standby automatic switchover operation. At the same time, the standby automatic switching device provided by this embodiment is the same as the previous standby automatic switching device. It is equipped with a bus differential protection action blocking signal. In a substation with a bus differential protection device, when the bus differential blocking action signal is received, the device can also be blocked. Standby automatic switching function, thus, the new device is compatible with the previous standby automatic switching device, which increases the reliability of the standby automatic switching operation and also increases the flexibility.

Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be implemented through computer programs to instruct related hardware, and the programs can be stored in a computer-readable storage medium. During execution, it may include the processes of the embodiments of the above-mentioned methods. Wherein, the storage medium may be a magnetic disk, an optical disk, a read-only memory (Read-Only Memory, ROM) or a random access memory (Random Access Memory, RAM), etc.

The above disclosure is only a preferred embodiment of the present invention, which certainly cannot limit the scope of rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope of the present invention.

Claims (7)

1. detect a method for fault inside and outside bus-bar area based on GPS locking phase differential method, it is characterized in that, comprising:

Judge that electric system is broken down, described electric system comprises: bus-bar area and land;

According to forward-order current fault component after GPS locking phase differential method acquisition fault relative to the phasing degree β of Pre-fault load current;

Size between more described phasing degree β and preset definite value δ; Described definite value δ flows to according to line parameter circuit value and trend and arranges;

If phasing degree β is greater than δ, then judge fault outside bus-bar area; Otherwise, judge bus-bar area internal fault; Wherein, described judgement electric system is broken down, and comprising:

Whether the amplitude of variation detecting bus composite voltage is greater than composite voltage amplitude of variation threshold value; Or whether described bus three-phase voltage is lower than three-phase voltage low pressure threshold;

If the amplitude of variation of described bus composite voltage is greater than described composite voltage amplitude of variation threshold value, or described bus three-phase voltage is lower than three-phase voltage low pressure threshold; Then whether detection line electric current uprushes and overcurrent further;

If line current is uprushed and overcurrent, then judge that described electric system is broken down; Otherwise, judge that described electric system is normal.

2. the method for fault inside and outside bus-bar area is detected as claimed in claim 1 based on GPS locking phase differential method, it is characterized in that, describedly obtain forward-order current fault component after fault according to GPS locking phase differential method and, relative to the phasing degree β of Pre-fault load current, comprising:

When described electric system normally runs, by GPS precision time service equipment, periodically detect the phasing degree of load current;

After the described electric system of judgement is broken down, the phasing degree of forward-order current fault component after detection failure;

According to forward-order current fault component after GPS locking phase differential method acquisition fault relative to the phasing degree β of Pre-fault load current.

3. detect the method for fault inside and outside bus-bar area as claimed in claim 1 based on GPS locking phase differential method, it is characterized in that, if described phasing degree β is greater than δ, then judge fault outside bus-bar area; Otherwise, after judging bus-bar area internal fault, also comprise:

If judge bus-bar area internal fault, then locking alternate power autocast operative installations action;

If fault outside judgement bus-bar area, trigger the action of alternate power autocast operative installations, standby power supply is started working, recover the normal power supply of bus institute on-load.

4. detect the method for fault inside and outside bus-bar area as claimed any one in claims 1 to 3 based on GPS locking phase differential method, it is characterized in that, described bus-bar area internal fault comprises: bus-bar fault and outgoing line side fault.

5. detect an alternate power autocast operative installations for fault inside and outside bus-bar area based on GPS locking phase differential method, it is characterized in that, comprising:

System failure judge module, for judging whether electric system breaks down, described electric system comprises: bus-bar area and land;

Phasing degree processing module, for obtaining after fault forward-order current fault component relative to the phasing degree β of Pre-fault load current according to GPS locking phase differential method; And the size between more described phasing degree β and preset definite value δ; Described definite value δ flows to according to line parameter circuit value and trend and arranges;

Abort situation judge module, for when described phasing degree β is greater than δ, judges fault outside bus-bar area; Otherwise, judge bus-bar area internal fault; Described bus-bar area internal fault comprises: bus-bar fault and outgoing line side fault;

Wherein, described system failure judge module comprises:

First detecting unit, whether the amplitude of variation for detecting bus composite voltage is greater than composite voltage amplitude of variation threshold value; Or whether described bus three-phase voltage is lower than three-phase voltage low pressure threshold;

Second detecting unit, for detecting that at described first detecting unit the amplitude of variation of described bus composite voltage is greater than described composite voltage amplitude of variation threshold value, or described bus three-phase voltage lower than three-phase voltage low pressure threshold time, whether further detection line electric current uprushes and overcurrent;

Judging unit, for uprush at described line current and overcurrent time, judge that described electric system is broken down; Otherwise, judge that described electric system is normal.

6. detect the alternate power autocast operative installations of fault inside and outside bus-bar area as claimed in claim 5 based on GPS locking phase differential method, it is characterized in that, described phasing degree processing module comprises:

GPS unit, for by GPS for correlation unit module provides time service;

Phasing degree detection module, for the time service according to described GPS unit, when described electric system normally runs, periodically detects the phasing degree of load current; And after described electric system is broken down, the phasing degree of forward-order current fault component after detection failure;

Phasing degree β acquisition module, for obtaining after fault forward-order current fault component relative to the phasing degree β of Pre-fault load current according to GPS locking phase differential method.

7. the alternate power autocast operative installations detecting fault inside and outside bus-bar area based on GPS locking phase differential method according to any one of claim 5 to 6, it is characterized in that, described device also comprises:

Prepared auto restart control module, for when judging bus-bar area internal fault, the action of locking alternate power autocast operative installations; When judging fault outside bus-bar area, triggering the action of alternate power autocast operative installations, standby power supply is started working, recovering the normal power supply of bus institute on-load.